Colorectal cancer (CRC) screening saves lives yet remains underutilized in the United States, with approximately 1 in 3 eligible Americans remaining unscreened. Prior research has documented numerous barriers to CRC screening, including patient factors (i.e., lack of awareness of screening options, negative attitudes and beliefs, low health literacy) and provider/system factors (i.e., lack of physician time, scheduling barriers, absence of after-visit patient support). Prior attempts to increase CRC screening have generally targeted either patient or provider/system barriers, with only modest results. To achieve the highest screening rates possible, a multilevel intervention that is time-efficient, easily implemented, and appropriate for varying literacy levels is urgently needed. The increasing popularity of user-friendly mobile devices makes mHealth, or the use of mobile technology to enhance patient care, an attractive option. We have designed an innovative low cost intervention to increase the receipt of CRC screening by leveraging mobile technology to inform, activate, and support patients before, during, and after their primary care visits. Our intervention can be easily disseminated and implemented in primary care practices and is appropriate for patients of all literacy levels. This project will evaluate the efficacy of our innovative multilevel mHealth CRC screening intervention (mCRC). The conceptual framework for the mCRC system is based on the social cognitive model emphasizing reciprocal determinism, or the dynamic interaction of the person, the behavior, and the environment. The mCRC system includes: 1) a tablet CRC screening decision aid that will collect patient information, deliver a screening message, and allow patients to make a screening decision; 2) self-service protocols that empower staff to order patient-requested screening tests; and 3) post-decision follow-up support for patients via automated and interactive text messaging. We will test the mCRC system in a randomized controlled trial conducted in community-based primary care practices serving a racially and socioeconomically diverse population. Patients will be randomized to either the mCRC system or a tablet educational program about healthy lifestyle habits. The trial will evaluate: 1) the ability of the mCRC system to increase receipt of CRC screening within 24 weeks as confirmed by medical chart reviews; 2) the potential mechanisms of change by which the mCRC system facilitates screening (i.e., patient ability to form a screening decision, patient attitudes and beliefs, patient self-efficacy, patient intention, and the occurrence of patient-provider CRC screening discussions); and 3) the additional cost of the mCRC system per patient screened, focusing on the system costs of staff time and technology. At the completion of our study, we will make the mCRC system freely available to help increase CRC screening and improve public health.